1. Field of the Invention
The present invention relates to an inside rearview mirror assembly for use in the passenger compartment or cabin of a motor vehicle, and more particularly to an attachment structure for such an inside rearview mirror assembly.
2. Description of the Relevant Art
Generally, an inside rearview mirror assembly mounted in the passenger compartment of a motor vehicle such as an automobile includes a base fixed to a vehicle body portion such as the upper end of a windshield or the front end of a compartment roof, and a stay connected to the base and holding a mirror.
When the motor vehicle collides with another motor vehicle or some other object, the head of the driver of the motor vehicle tends to hit the inside rearview mirror assembly. To protect the driver's head in such an accident, the inside rearview mirror assembly of such a structure is required to allow the stay to come off the base when abnormal external forces are imposed on the stay.
One such a collapsible inside rearview mirror assembly is disclosed in Japanese Laid-Open Utility Model Publication No. 55-85339, for example. The disclosed inside rearview mirror assembly includes a resilient member comprising a leaf spring attached to a stay and held in engagement with a base, thus assembling the stay and the base together. When the stay is subjected to abnormal external forces applied, the stay is forced to slide with respect to the base, permitting the resilient member to be separated from the base and hence the stay to drop off.
When the stay drops off the base, the stay slides with respect to the base against a relative frictional force therebetween. Since such a frictional force is determined dependent on a plurality of factors such as the surface roughness of each of the contact surfaces of the stay and the base, the area of contact between the stay and the base, and the like. Therefore, it is difficult to stabilize the load or force required to cause the stay to come off the base.